ExpressionVisitor.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / Core / System / Linq / Expressions / ExpressionVisitor.cs / 1305376 / ExpressionVisitor.cs
                        

                        
                            using System; 
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Reflection;
 
// Include Silverlight's managed resources
#if SILVERLIGHT 
using System.Core; 
#endif //SILVERLIGHT
 
namespace System.Linq.Expressions {

    //
    internal abstract class OldExpressionVisitor { 
        internal OldExpressionVisitor() {
        } 
 
        internal virtual Expression Visit(Expression exp) {
            if (exp == null) 
                return exp;
            switch (exp.NodeType) {
                case ExpressionType.UnaryPlus:
                case ExpressionType.Negate: 
                case ExpressionType.NegateChecked:
                case ExpressionType.Not: 
                case ExpressionType.Convert: 
                case ExpressionType.ConvertChecked:
                case ExpressionType.ArrayLength: 
                case ExpressionType.Quote:
                case ExpressionType.TypeAs:
                    return this.VisitUnary((UnaryExpression)exp);
                case ExpressionType.Add: 
                case ExpressionType.AddChecked:
                case ExpressionType.Subtract: 
                case ExpressionType.SubtractChecked: 
                case ExpressionType.Multiply:
                case ExpressionType.MultiplyChecked: 
                case ExpressionType.Divide:
                case ExpressionType.Modulo:
                case ExpressionType.Power:
                case ExpressionType.And: 
                case ExpressionType.AndAlso:
                case ExpressionType.Or: 
                case ExpressionType.OrElse: 
                case ExpressionType.LessThan:
                case ExpressionType.LessThanOrEqual: 
                case ExpressionType.GreaterThan:
                case ExpressionType.GreaterThanOrEqual:
                case ExpressionType.Equal:
                case ExpressionType.NotEqual: 
                case ExpressionType.Coalesce:
                case ExpressionType.ArrayIndex: 
                case ExpressionType.RightShift: 
                case ExpressionType.LeftShift:
                case ExpressionType.ExclusiveOr: 
                    return this.VisitBinary((BinaryExpression)exp);
                case ExpressionType.TypeIs:
                    return this.VisitTypeIs((TypeBinaryExpression)exp);
                case ExpressionType.Conditional: 
                    return this.VisitConditional((ConditionalExpression)exp);
                case ExpressionType.Constant: 
                    return this.VisitConstant((ConstantExpression)exp); 
                case ExpressionType.Parameter:
                    return this.VisitParameter((ParameterExpression)exp); 
                case ExpressionType.MemberAccess:
                    return this.VisitMemberAccess((MemberExpression)exp);
                case ExpressionType.Call:
                    return this.VisitMethodCall((MethodCallExpression)exp); 
                case ExpressionType.Lambda:
                    return this.VisitLambda((LambdaExpression)exp); 
                case ExpressionType.New: 
                    return this.VisitNew((NewExpression)exp);
                case ExpressionType.NewArrayInit: 
                case ExpressionType.NewArrayBounds:
                    return this.VisitNewArray((NewArrayExpression)exp);
                case ExpressionType.Invoke:
                    return this.VisitInvocation((InvocationExpression)exp); 
                case ExpressionType.MemberInit:
                    return this.VisitMemberInit((MemberInitExpression)exp); 
                case ExpressionType.ListInit: 
                    return this.VisitListInit((ListInitExpression)exp);
                default: 
                    throw Error.UnhandledExpressionType(exp.NodeType);
            }
        }
 
        internal virtual MemberBinding VisitBinding(MemberBinding binding) {
            switch (binding.BindingType) { 
                case MemberBindingType.Assignment: 
                    return this.VisitMemberAssignment((MemberAssignment)binding);
                case MemberBindingType.MemberBinding: 
                    return this.VisitMemberMemberBinding((MemberMemberBinding)binding);
                case MemberBindingType.ListBinding:
                    return this.VisitMemberListBinding((MemberListBinding)binding);
                default: 
                    throw Error.UnhandledBindingType(binding.BindingType);
            } 
        } 

        internal virtual ElementInit VisitElementInitializer(ElementInit initializer) { 
            ReadOnlyCollection arguments = this.VisitExpressionList(initializer.Arguments);
            if (arguments != initializer.Arguments) {
                return Expression.ElementInit(initializer.AddMethod, arguments);
            } 
            return initializer;
        } 
 
        internal virtual Expression VisitUnary(UnaryExpression u) {
            Expression operand = this.Visit(u.Operand); 
            if (operand != u.Operand) {
                return Expression.MakeUnary(u.NodeType, operand, u.Type, u.Method);
            }
            return u; 
        }
 
        internal virtual Expression VisitBinary(BinaryExpression b) { 
            Expression left = this.Visit(b.Left);
            Expression right = this.Visit(b.Right); 
            Expression conversion = this.Visit(b.Conversion);
            if (left != b.Left || right != b.Right || conversion != b.Conversion) {
                if (b.NodeType == ExpressionType.Coalesce && b.Conversion != null)
                    return Expression.Coalesce(left, right, conversion as LambdaExpression); 
                else
                    return Expression.MakeBinary(b.NodeType, left, right, b.IsLiftedToNull, b.Method); 
            } 
            return b;
        } 

        internal virtual Expression VisitTypeIs(TypeBinaryExpression b) {
            Expression expr = this.Visit(b.Expression);
            if (expr != b.Expression) { 
                return Expression.TypeIs(expr, b.TypeOperand);
            } 
            return b; 
        }
 
        internal virtual Expression VisitConstant(ConstantExpression c) {
            return c;
        }
 
        internal virtual Expression VisitConditional(ConditionalExpression c) {
            Expression test = this.Visit(c.Test); 
            Expression ifTrue = this.Visit(c.IfTrue); 
            Expression ifFalse = this.Visit(c.IfFalse);
            if (test != c.Test || ifTrue != c.IfTrue || ifFalse != c.IfFalse) { 
                return Expression.Condition(test, ifTrue, ifFalse);
            }
            return c;
        } 

        internal virtual Expression VisitParameter(ParameterExpression p) { 
            return p; 
        }
 
        internal virtual Expression VisitMemberAccess(MemberExpression m) {
            Expression exp = this.Visit(m.Expression);
            if (exp != m.Expression) {
                return Expression.MakeMemberAccess(exp, m.Member); 
            }
            return m; 
        } 

        internal virtual Expression VisitMethodCall(MethodCallExpression m) { 
            Expression obj = this.Visit(m.Object);
            IEnumerable args = this.VisitExpressionList(m.Arguments);
            if (obj != m.Object || args != m.Arguments) {
                return Expression.Call(obj, m.Method, args); 
            }
            return m; 
        } 

        internal virtual ReadOnlyCollection VisitExpressionList(ReadOnlyCollection original) { 
            List list = null;
            for (int i = 0, n = original.Count; i < n; i++) {
                Expression p = this.Visit(original[i]);
                if (list != null) { 
                    list.Add(p);
                } 
                else if (p != original[i]) { 
                    list = new List(n);
                    for (int j = 0; j < i; j++) { 
                        list.Add(original[j]);
                    }
                    list.Add(p);
                } 
            }
            if (list != null) 
                return list.ToReadOnlyCollection(); 
            return original;
        } 

        internal virtual MemberAssignment VisitMemberAssignment(MemberAssignment assignment) {
            Expression e = this.Visit(assignment.Expression);
            if (e != assignment.Expression) { 
                return Expression.Bind(assignment.Member, e);
            } 
            return assignment; 
        }
 
        internal virtual MemberMemberBinding VisitMemberMemberBinding(MemberMemberBinding binding) {
            IEnumerable bindings = this.VisitBindingList(binding.Bindings);
            if (bindings != binding.Bindings) {
                return Expression.MemberBind(binding.Member, bindings); 
            }
            return binding; 
        } 

        internal virtual MemberListBinding VisitMemberListBinding(MemberListBinding binding) { 
            IEnumerable initializers = this.VisitElementInitializerList(binding.Initializers);
            if (initializers != binding.Initializers) {
                return Expression.ListBind(binding.Member, initializers);
            } 
            return binding;
        } 
 
        internal virtual IEnumerable VisitBindingList(ReadOnlyCollection original) {
            List list = null; 
            for (int i = 0, n = original.Count; i < n; i++) {
                MemberBinding b = this.VisitBinding(original[i]);
                if (list != null) {
                    list.Add(b); 
                }
                else if (b != original[i]) { 
                    list = new List(n); 
                    for (int j = 0; j < i; j++) {
                        list.Add(original[j]); 
                    }
                    list.Add(b);
                }
            } 
            if (list != null)
                return list; 
            return original; 
        }
 
        internal virtual IEnumerable VisitElementInitializerList(ReadOnlyCollection original)
        {
            List list = null;
            for (int i = 0, n = original.Count; i < n; i++) 
            {
                ElementInit init = this.VisitElementInitializer(original[i]); 
                if (list != null) 
                {
                    list.Add(init); 
                }
                else if (init != original[i])
                {
                    list = new List(n); 
                    for (int j = 0; j < i; j++)
                    { 
                        list.Add(original[j]); 
                    }
                    list.Add(init); 
                }
            }
            if (list != null)
                return list; 
            return original;
        } 
 
        internal virtual Expression VisitLambda(LambdaExpression lambda)
        { 
            Expression body = this.Visit(lambda.Body);
            if (body != lambda.Body) {
                return Expression.Lambda(lambda.Type, body, lambda.Parameters);
            } 
            return lambda;
        } 
 
        internal virtual NewExpression VisitNew(NewExpression nex) {
            IEnumerable args = this.VisitExpressionList(nex.Arguments); 
            if (args != nex.Arguments) {
                if(nex.Members != null)
                    return Expression.New(nex.Constructor, args, nex.Members);
                else 
                    return Expression.New(nex.Constructor, args);
            } 
            return nex; 
        }
 
        internal virtual Expression VisitMemberInit(MemberInitExpression init) {
            NewExpression n = this.VisitNew(init.NewExpression);
            IEnumerable bindings = this.VisitBindingList(init.Bindings);
            if (n != init.NewExpression || bindings != init.Bindings) { 
                return Expression.MemberInit(n, bindings);
            } 
            return init; 
        }
 
        internal virtual Expression VisitListInit(ListInitExpression init) {
            NewExpression n = this.VisitNew(init.NewExpression);
            IEnumerable initializers = this.VisitElementInitializerList(init.Initializers);
            if (n != init.NewExpression || initializers != init.Initializers) { 
                return Expression.ListInit(n, initializers);
            } 
            return init; 
        }
 
        internal virtual Expression VisitNewArray(NewArrayExpression na) {
            IEnumerable exprs = this.VisitExpressionList(na.Expressions);
            if (exprs != na.Expressions) {
                if (na.NodeType == ExpressionType.NewArrayInit) { 
                    return Expression.NewArrayInit(na.Type.GetElementType(), exprs);
                } 
                else { 
                    return Expression.NewArrayBounds(na.Type.GetElementType(), exprs);
                } 
            }
            return na;
        }
 
        internal virtual Expression VisitInvocation(InvocationExpression iv) {
            IEnumerable args = this.VisitExpressionList(iv.Arguments); 
            Expression expr = this.Visit(iv.Expression); 
            if (args != iv.Arguments || expr != iv.Expression) {
                return Expression.Invoke(expr, args); 
            }
            return iv;
        }
    } 

    // 
    internal static class ReadOnlyCollectionExtensions { 
        internal static ReadOnlyCollection ToReadOnlyCollection(this IEnumerable sequence) {
            if (sequence == null) 
                return DefaultReadOnlyCollection.Empty;
            ReadOnlyCollection col = sequence as ReadOnlyCollection;
            if (col != null)
                return col; 
            return new ReadOnlyCollection(sequence.ToArray());
        } 
        private static class DefaultReadOnlyCollection { 
            private static ReadOnlyCollection _defaultCollection;
            internal static ReadOnlyCollection Empty { 
                get {
                    if (_defaultCollection == null)
                        _defaultCollection = new ReadOnlyCollection(new T[] { });
                    return _defaultCollection; 
                }
            } 
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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